Method and means for utilizing thermionic tubes having open filaments



Aug. 23, 1932. H, JQHNSQN 1,873,711

METHOD AND MEANS FOR UTILIZING THERMIONIC TUBES HAVING OPEN FILAMENTS Filed June 18, 1928 ummunyl 59 a fifiw 158 in. v mam 37 29 1n venior Witnesses: RudoQa/z 10/025077.

law W Hi5 A Horn ey- Patented Aug. 23, 1932 "UNITED STATES PATENT oFFw 1mm: H. .ronuson, or cnrcaoo, IL'Lmo s METHOD AND MEANS non UTILIZING 'I'Imm omc TUBES HAVING 01am:

"application filed June 1;, i928. Serial no. 286,089."

My invention relates-to methods and means for utilizing thermionic. tubes having open filaments, its general object being the provision of a comparatively simple and ini 5 expensive device whichwill permit the con-' tinued use of thermionic tubes after the filamentsthereof have been burned out, or otherwise destroyed. i i

,,.Another.object ofm'y invention is to cf- 30 feet a substantial saving in the equipment required 'for charging storage batteries by making. use of burnt out bulbs, hitherto'considered as valueless for rectifyin purposes. v Other objects and advantages theinvention will appear more fully in the hereinafter specification 1 when taken in connection with the accompanying drawing, in which f Figure 1 is a diagrammatic view of a, circuit showing a rectifying bulb with its glass g9 envelope partly in section and partly broken away, incorporated therein; 7

Figure 2 is adiagrammatic view of a modified form of a circuit, showing a rectifying bulb in perspective embodied therein. Figure'31s a. diagrammatic view of another modified method and means for accomplishing the object of my-invention.

In the drawing, wherein similar characw ters of reference indicate corresponding j 39 parts in the views, 4 designates theprimary of a transformer, A.-the terminals 5 and 6 of which are connected to an alternating current source of potential. B designates the secondary of the transformer, the secondary being tapped at the point 7 in order to provide a source of comparatively low potential for charging purposes, as will here inafter appear. p

Referring to Figure 1, the circuit 8 includes a switch 9, a spark-gap 10, the rectifying bulb'11 and the storage battery 12. It will be observed that when the primary 4 of the transformer A is energized, a current of high potential will traverse the circuit 8 when the switch 9 is closed, the current bridging the gap between thecathode 13 and the anode 14. The cathode in thefpresent case ma be either half of the open filament 13' an its attached supporting rod connected to the base 11. The condenser 15, as is usual in these circuits, merely'serves to facilitate the building up of potentials, suitable for passing'over the spark-gap and the space between the electrodes 13 and 14 within the rectifying bulb; Itis to be observed that after the current hasbeen flashed across the electrodes 13 and 14 in the tube, the switch 9 maybe opened, leaving the secondary circuit to be completedthroughthe right. hand Wing 16 of the'secondary B, thepotential in this wing being suitable for ordinary battery charging. The lead from the tapping 7 ex; tends to a point between the. spark gap 10 and rectifying'bulb 11 so as to provide a cur; rent of low potential utilizing only theright hand Wing 16 when the main circuit including the switch9 is open. Tofacilitatethis operation, the lead from the tapping 7 is provided with a switch 7 which is opened when a current of high potential is established by closing switch, 9, but which is closed to maintain a current of low potentialwhen switch 9 isopen. i

In Figure 2, 17 designates the primary of the transformer, one terminal 18 of which is suitably connected to a conventional switch 19, the other terminal 20 of the primary leading to a source of alternating current. When the switch 19 is closed, an alternating current will flow in the primary 17 thereby inducing a high voltage, secondary current to flow in the secondary circuit 21 which includes the condenser 22, the spark-gap 23 and the rectifying bulb 24. Prior to the closing of the switch 19, the customary potential in the alternating current mains will be insufiicient to pass current through the primary cir- CuitJWhlCh includes the batter 27, the elec trodes 25 and 26 of the recti ying bulb 24, and the return lead 28 to the mains. How- 90 ever,"whenthe switch 19 is closed the induced high potential will immediately pass current across the spark-gap 23 and the electrodes 25 and'26, after which the low potential current will flow through the tube in the usualmanner, when'thesw'itch 19 is thrown open, thereby eliminating current from the secondary circuit 21. If desired, conventional relays may be employed instead of t wi he 9 a d the e ay r i to automatically cut out the high potential circuit when low potential current begins to pass through the bulb.

Heretofore, after a period equivalent to about one thousand hours of use, the filament of the average rectifying bulb of the typeindicated is either burned out or has become fragile to a point where its fracture has occurred. As is well known, rectifying bulbs of the type indicated, especially the larger size, are e tpensive and their frequent replacement 11) commercial establishments involves a considerable financial outlay. Following the usual practice, upon the burning out or fracture of the filament, the bulbs were discard ed. the method and means herein indicated, it is to be noted that these rectifying bulbsmay be now reeniployed, even after the filaments have been fractured, as illustrated. The life of these tubes may now be prolonged to a point dependent only upon the current conducting properties of the gas within the glass envelope. The rectifying :results obtained are approximately equal in most cases to those obtaned by the bulb prior ,compact 130K or casing, these being supplied with a convenient handle for carrying about.

In Figure 3,29, 80, designate the primary and secondary windin s, respectively, of a step-down transformer, the winding 30 of which I connect to the primary 31 of a conventional spark coi.

vransformer D, one of the terminals 33 of the secondary 32 of the latter being led to the open filament 3 the other secondary being connected through spark gap to the anode d of the rectifying bulb 37. On inspection. of Figure 3 it will now be observed that when the terminals 29 of the primary of the step-down transformer are energized by alternating current from the mains, current will be supplied the spark coil transformer D, causing a high potential current to flash across spark gap 35 and to bridge the spac between the anode and filament of the bu b 37, thereby breakdown the initi l resi ance offered to the patsage of a current between the electrodes of the bulb, whereupon the circuit 38 wired in parallel with the primary 29, and including the battery 39, will now permit alternating current direct from the mains to pass between the electr des of the bulb 37 for the purpose of charging the battery in the usual manner.

I am aware of rectifyinx thermionic bulbs, particularly of the gaseous type, which do not employ filaments, but the method now employ for the continued use of rectifying bulbs having open filaments, I believe to be original in the related industry.

It will be obvious tothose skilled in the art to which my invention appertains, that modification and change may be made in the circuits and instrumentalities employed for the achievement of the objects I have indicated; hence I do not confine myself to the details precisely as set forth only in so far as they are circumscribed by the appended claims.

lVhat I claim is new and desire to secure by Letters Patent:

1. A rectifying circuit of the character described, comprising a transformer having a primary directly connected to an alternating current supply and a secondary tapped to provide two branch secondary circuits, the first of said secondary branch circuits provided with separated electrodes to establish a spark gap, a rectifying tube connected in the main circuit including said second secondary branch circuit, said rectifying tube requiring a higher initial energizing potential than normally induced in said second branch secondary circuit, a lead from the tapping between said secondary portions to the main circuit, a switch in said first secondary branch circuit between said secondary and said lead connection for establishing a current of high potential, a switch in said lead adapted to be closed to maintain a current of low potential when said first mentioned switch open, and a rectified current receiving device connected in series with said rectifying tube in said second secondary branch circuit.

2. A rectifying circuit of the character described, comprising a transformer having a 1 primary directly connected to an alternating current supply and a secondary tapped to provide two branch secondary circuits, the first of said secondary branch circuits provided with separated electrodes to establish a spark gap, a rectifying tube connected in the main circuit including said second secondary branch circuit, said rectifying tube requiring a higher initial energizing potential than normally induced in said second branch secondary circuit, a lead from the tapping between said secondary portions to the main circuit, a switch in said first secondary branch circuit between said secondary and said lead connection for establishing a current of high potential, a switch in said lead adapted to be closed to maintain a current of low poten tial when said first mentioned switch is open, a rectified current receiving device connected in series with said rectifying tube in said second secondary branch circuit, and a condenser shunted across the conductors leading to said rectifying tube and rectified current receiving device.

In testimony whereof I have signed my name to this specification. 

